The present invention relates to a method for manufacturing a striped phosphor screen for a black matrix type color picture tube and an apparatus for coating phosphor material in a stripe pattern.
When a phosphor screen of a color picture tube is formed, a method has been usually used, in which grains of a phosphor material are suspended in a photosensitive solution containing an aqueous solution of a mixture of polyvinyl alcohol and ammonium bichromate to prepare a slurry, which is then uniformly applied on the inner surface of a panel of the color picture tube, and the applied slurry is exposed through a shadow mask to render only the exposed areas insoluble, and the slurry is developed to leave a desired picture element pattern. The above process is repeated for each of the phosphor materials of three primary colors, i.e. green, blue and red.
However, in such a prior art manufacturing method, in addition to long process time required to form each color of picture elements including slurry application, drying, exposure, development and drying, many problems occur relating to process control and facility control because the above process is repeated for each of the three primary colors. Furthermore, for a black matrix type color picture tube, it is necessary to provide a light absorbing material on those areas on the inner surface of the panel which do not correspond to the three primary colors picture elements before a phosphor pattern is formed. Since this process also needs application of a light absorbing material, exposure, development and drying, a long process time is required for both the formation of the phosphor pattern and the formation of the light absorbing pattern. Accordingly, the rationalization of workability and facilities has not been attained and hence the cost could not be reduced.